Preparation and Mounting of Vegetable Tissues 17& 



motion, to spread the raphides evenly between the cover 

 and slide. Put away for an hour or two, scrape off the 

 excess of jelly with a penknife, wash in water, and then in 

 methylated spirit, dry with a cloth, and apply a coat of 

 black enamel. When raphides in the tissues are prepared 

 in glycerine jelly, wash away all trace of spirit with water,, 

 and mount in glycerine jelly as above. 



Starches {Isolated Speeimens). — If the tissue is fresh, 

 scrape the cut surface with a knife, and place the scrapings 

 in a bottle of water ; shake well and then strain through 

 fine muslin into a shallow vessel ; let the starch settle, pour 

 off the water, and wash again with some clean water until 

 the starch is quite clean ; then place it in a bottle, and 

 when it has settled to the bottom, pour off the water, and 

 add methylated spirit. 



Dried Specimens. — Place in water until the tissue swells- 

 up, then, if the material is large enough, it may be scraped 

 and treated as above. If too small — small seeds, for 

 instance — place them in a mortar in some water, and 

 carefully break them up ; strain through muslin, wash with 

 water until quite clean, and preserve in methylated spirit. 



Starches may be mounted in Canada balsam or glycerine 

 jelly. If the former is chosen, spread a little starch evenly 

 on a cover-glass, let it dry, apply some Canada balsam, and 

 mount it in the ordinary way. For glycerine jelly pour off 

 the spirit and add water, then allow the starch to settle to 

 the bottom of the bottle ; pour away the water. Place a 

 few drops of glycerine jelly on a slide, take up some starch 

 on a penknife, and place it in a little heap in the jelly ; now 

 apply a cover-glass, and press down with a gentle twisting 

 movement until the starch is evenly spread. Let the jelly 

 set, scrape away the excess, wash in water, then in spirit, 

 dry, and apply a coat of cement. 



It is desirable also to prepare specimens of starch in situ 

 in the tissues. Take, for example, a potato, cut it into small 

 piecQS of about half an inch square, and harden them in 

 methylated spirit. Then embed in carrot and cut the 



12—2 



